Ever wonder if VARCHAR(255) or TEXT is a better data type? This thread suggests VARCHAR(255) is better because it is allowed to use MEMORY (or RAM). The TEXT data type is not allowed in there.
Although it was also found that a larger VARCHAR like VARCHAR(3000) has worse performance than TEXT (in MyISAM).
The general rule appears to be to use VARCHAR if it is less than 255 characters and to use TEXT if it’s 255 or more.